SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb90a2e30343de0bf09d918d5e7cd0a05ff3c18a14b10b6ab08147ced39a6b7d' 
  AND token = 'A2/wSzIPaVDA67ZhYbKNg0GdY4j3Q4OcvsUTzMh/UnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}